The present invention generally concerns a process for the production of bunches of artificial or natural hair, fibre or bristle material which is held together in the form of a bundle, for forming the heads of brushes of various sizes, and an apparatus for carrying out such a process.
In this specification, the hair, fibre or bristle or like material will be referred to generally as brush material to embrace such various kinds of material, while the bunches which are made up of such material or materials will be referred to for the sake of simplicity as a brush head.
My U.S. Pat. No. 3,836,199 discloses a process and an apparatus for producing brush heads from hairs or bristles as brush material, wherein a bundle or hairs or bristles is introduced into a perforated plate having a plurality of apertures therein, the plate referred to as an apertured plate, by means of the root ends of the hairs or bristles, with oscillations or vibrations being applied thereto, and then a pin-bearing plate which corresponds to the apertured plate and the pins on which correspond to the desired contour of the brush heads is inserted from below at the root end into the apertured plate. Oscillations or vibrations are also applied to the assembly when the pin plate is being introduced into the apertured plate. The bunches of hairs or bristles, or brush heads, which are formed in that way, are then provided at their root ends with a liquid binding agent and, after the layer of applied binding agent has set, the individual bunches or heads are successively ejected in groups from the apertured plate by means of a suitable ejector plate.
That process and apparatus however do not operate satisfactorily when producing bunches or brush heads from artificial brush material and also when producing bunches or brush heads from natural brush material when the amount of brush material in each bunch or brush head is less than a given amount. Natural hairs have regularly arranged, small, resilient projections or tangs on their outsides, and, when hairs are in closely juxtaposed relationship with each other, those projections or tangs cause the hairs to be resiliently mutually repelled while they also become hookingly engaged with each other to a certain degree. Such interlocking between the adjacent hairs causes a bunch of such hairs to have a certain amount of inherent stability and cohesion. That effect is utilised in the process briefly outlined above, in such a way that the individual hairs of a bundle thereof which is introduced into a holder, in spite of the difference in area of the aperture in the holder into which the hairs are fitted and the sum of the areas of the apertures in the apertured plate, due to the surface areas of the wall portions between the apertures in the apertured plate, stand upright in the holder although there are small spaces between the individual hairs in the bunch thereof. Furthermore, by virtue of the above-indicated effect of the projecting tangs on the outsides of natural hairs, the amount of hair in each bunch of hairs could be varied within certain limits, in spite of using the same apparatus, that is to say, with the same number and diameter of apertures for receiving the respective bunches of hairs. When the amount of hairs in a given bunch falls below a given limit value, the hairs have a tendency to lean towards the side, so that it is then no longer possible to provide for uniform distribution of the hairs in the apertures in the apertured plate, and it is likewise no longer possible to cause the hairs to lie correctly in the apertures in the apertured plate, under the effect of the applied oscillations or vibrations.
In contrast, the outsides of synthetic or artificial brush material or artificial hairs are smooth and do not have resilient projecting tangs as referred to above, so that the above-indicated effect of mutual repulsion of adjacent hairs no longer occurs. That means that, after a bunch of artificial brush material has been introduced into a holder therefor, the individual hairs, fibres, bristles or like brush material tend to lean in different directions in a disordered manner as the small spaces between the individual hairs, fibres, bristles or the like can no longer be filled up, as was the case with natural hair when the spaces in question were filled by the presence of the projecting tangs. The absence of the resilient repulsion effect is a particularly disadvantageous consideration when dealing with artificial hairs or the like which are of a conical or tapering shape. In that situation, the spaces between the hairs, bristles, fibres or the like brush material, which are already to be found at the root end thereof, increase continuously in size to the tips of the hairs or like brush material, so that random tilting of the artificial hairs or like brush material is still further increased.
By virtue of the fact that the contour of the bunches or brush heads is essentially produced by inserting a pin plate which is provided with correspondingly shaped pins adapted to engage into the respective bunches of brush material, substantial fluctuations in shape occur when using hairs of different lengths, which frequently happens when dealing with natural hairs.